Simplify the following expression: $p = \dfrac{10n^2 + 20n - 80}{n + 4} $
Explanation: First factor the polynomial in the numerator. We notice that all the terms in the numerator have a common factor of $10$ , so we can rewrite the expression: $ p =\dfrac{10(n^2 + 2n - 8)}{n + 4} $ Then we factor the remaining polynomial: $n^2 + {2}n {-8} $ ${4} {-2} = {2}$ ${4} \times {-2} = {-8}$ $ (n + {4}) (n {-2}) $ This gives us a factored expression: $\dfrac{10(n + {4}) (n {-2})}{n + 4}$ We can divide the numerator and denominator by $(n - 4)$ on condition that $n \neq -4$ Therefore $p = 10(n - 2); n \neq -4$